Dilatometer Testing in Highly Overconsolidated Soils

The dilatometer was first introduced by Marchetti in 1975. This new in situ device has a very large potential in evaluating some important soil properties. The knowledge of drainage conditions during penetration is an important part of the test results. Unfortunately, the dilatometer by itself cannot measure the pore pressure generated during penetration. Therefore, in order to determine what the drainage conditions were, a piezoblade was designed. This new piezometer has the same shape as a dilatometer. Many dilatometer and piezoblade tests were performed and the dilatometer's first pressure readings were compared to the generated excess pore pressures. From the test results, it appears that the maximum effect of generated excess pore pressure in very overconsolidated soil is about 40% of the dilatometer's first pressure reading.